1. Field of the Invention
The invention is in the field of medical apparatus for fixation and compression of a broken bone fragment relative to the principal bone.
2. Description of the Prior Art
In the prior art, several attempts have been made to anchor an intramedullary pin within the principal bone in the case of a bone fracture and to maintain the broken bone fragment adjacent the principal bone. Examples of such devices are shown in U.S. Pat. No. 3,763,855 to McAtee and U.S. Pat. No. 2,821,979 to Cameron. These devices require the insertion of a lateral element through the principal bone at a point distant from the location of the fracture.
The use of a surgical screw for bone fixation is shown in U.S. Pat. No. 2,612,159 to Collison. A different screw-type bone fixation device is shown in U.S. Pat. No. 3,779,239 to Fischer et al. Various other screw-type connectors for fractured bones with expanding-head connectors are shown in Fischer U.S. Pat. Nos. 3,678,925, 3,782,374, 3,716,051, and 3,805,775.
These prior art devices are generally more complicated than that disclosed in the present application, and often have the difficulty of not being capable of conformity to the bone contours without protrusions.